Method of forming a bow side for a boat



Dec. 13, 1960 R. L. FAIRBAIRN METHOD OF FORMING A BOW SIDE FOR A BOAT Filed May 13, 1958 2 Sheets-Sheet l Wmlh.

lry'verytor Roberi' L. Fqirbairn M KZ Dec. 13, 1960 R. L. 'FAIRBAIRN METHOD OF FORMING A BOW SIDE FOR A BOAT 2 Sheets-Sheet 2 Filed May 13. 1958 United States Patent METHOD OF FORMING A BOW SIDE FOR A BOAT Robert L. Fairbairn, Winnipeg, Manitoba, Canada (5919 Roblln.Blvd., Charleswood, Manitoba, Canada) Filed May 13, 1958, Ser. No. 734,963

2 Claims. (Cl. 96)

The use of aluminum sheathing has come into fairly general practice in the manufacture of small boats, such as rowboats and those powered by outboard motors, possibly due to its lightness of weight and lack of oxidation in the presence of water. Such boats can normally be built with the use of two sheets, same abutting, or lapped, along the keel while the bows are pressed to shape and so stretch the metal. As the bows must be bellied out, so to speak, or dished, metal stretching is unavoidable and the edges of the sheets crinkle badly and have to be trimmed off in a finishing operation. This crinkling or wrinkling is so bad that approximately 40% of the material must be trimmed as waste. As the bows of a boat receive the greatest water pressure, when in operation, various means have been employed to strengthen the bows, such as the use of heavier sheets, which is also very expensive, or by welding a strenghtening rib therewithin. Welding aluminum is very difficult, the heat anneals or softens the sheet from four to six inches on each side of the weld while the torch may easily burn through a sheet. The front of the boat may become bow-heavy as the rib is necessarily thick.

The principal objects of the present invention are: to press a groove, and so form a rib, into the sheathing on each side of the boat, at the bow portion thereof, for added strength; and so also draw the sheathing into the bow-shape, without crinkling the edges thereof and save so much material loss; retain bow lightness; amply reinforce the bows to withstand the pressure and butfeting of the water; and also pennit the use of reasonably light material and reduce the cost of manufacture.

Still further objects of the invention are: to accomplish the above mentioned objects in a simple and economical manner; maintain the said bows water-tight and sea worthy; and at the same time present a pleasing groove design on the bow exteriors which will also have the tendency to reduce spray splash into the boat; and be constantly washed clean.

With the above important, and other minor oblects in i which will become more apparent as the description proceeds, the invention consists essentially in the method of forming the groove, or rib, and shaping the material to fit the boat framework, reference being bad to the accompanying drawings in which:

Figure l is a side view of the bow of a boat with the reinforcing groove shown thoreom Figure 2 is a partial cross-sectional View taken on the line 2-2 of Figure 1.

Figure 3 is a partial perspective view of the how end of a sheet, showing the shape of the reinforcing rib.

Figure 4 is a similar view to Figure 3 but showing the end of the sheet further formed.

Figure 5 is a partial plan view of a boat bow, minus the deck, and showing how the sheets overlap.

Figure 6 is a partial perspective view looking into the bows of the boat.

Figure 7 is an enlarged vertical section taken on the line 7-7, Figure 6.

2,963,717 Patented Dec. 13, 1960 Figure 8 is a partial perspective view of the dies for forming the reinforcing rib in a sheet.

Figure 9 is a plan view of a trimmed sheet ready for forming.

In the drawings like characters of reference indicate corresponding parts in the several figures.

The bow, or prow portion, of a metal boat is indicated generally by the reference 10 in Figures 1 and 6. In the present instance, the framework of said boat is formed from wood and consists of a central stem 11, the upper end of which is secured to a triangular-shaped knee, or corner block, 12. It then passes down from the knee in a curve to terminate on the front of the fioorboard 13. The sides of the knee block receives a pair of inwales 14, one on each side, while an outwale 15 is provided on the outer side of each inwale and their forward ends extend ahead and abut in front of the stem. These wales form the gunwales. A pair of seat rails 16 and 17, one on each interior side of the boat, abut the stem and are positioned some distance below the gunwales and curve outwardly and rearwardly in the same manner. A pair of sheets 18 and 19 are each shaped to form a side of the boat, their upper edges being received between the wales 14 and 15, then pass down over the seat rails 16 and 17 where outer splash rails 20 and 21 are secured, and then their lower edges lap along the central bottom and up the stem to the boat nose. A sealing fabric, or mastic (not shown) is usually inserted between the lapped edges. A keel strip 22 covers these lapped joints on the bottom and a nosing strip 23 continues from the keel up the front to the boat nose. Further sister keels, or rub strips, (not shown) are also standard design. one on either side of the main keel, and all keels are suitably fastened (not shown) to the floor plate. A short deck 24 usually extends over the bows, from the nose. as a finish. The above is well known construction in boat building.

As previously mentioned, the usual methOd of forming the front ends of the sheets 18 and 19 into the required bow shape is by pressing same to expand or stretch the metal. This stretching crinkles the sheet edges and they must be trimmed off to the correct design, thus losing a lot of valuable material. The stretching also obviously thins the sheets, especially at the points where the greatest water pressure is received in the operation of the boat. If ribs are welded to the interior parts of the sheets at the bows, this results in a heavy front end, heat weakening of the metal, and the welding torch may cut through the sheet. Welding aluminum is a difficult operation at any The method employed in the present invention is to first trim the sheets to a pre-determined design, then press a streamlined tapered groove into the sheet metal itself from the outer side and so form an interior reinforcing rib at the bow part thereof, without crinkling the edges of the sheets, with very little if any increase of how weight, no excessive trimming, while at the same time the operation pulls the sheet into the desired bowshape, without stretching this part of the sheet and so retaining its original thickness. The details of the method used and the mechanism employed will now be fully described, although it is to be understood and appreciated thatl do not wish to be limited to the precise details of the die construction, except as embodied in the appended claims.

Figure 8 shows the principal-parts of the dies for producing'the grooves in the sheets. A pair of lower beams 25 and 26 are secured side by side and their upper edges are centrally cut away in a curve, indicated at 27. A

steel knife-shaped plate 28 is secured between the beams, at the cut-away portion. One end of said plate is flush with the beams and it then gradually projects therefrom in a curve along the cut-away portion, finally reaching its greatest height therefrom at the other end. A pin 29 IS provided adjacent this latter end and extends upwardly from the blade. The above comprises the male die.

A beam 30 passes across one of the ends of the male die, adjacent the fiush end of the knife plate, and its supports the lower edge of a sloping platform 31. Each end of this beam is provided with a vertical hole 32 theredown and one of said holes receives a guide stake 33.

The female die consists of a further pair of beams 34 and 34', secured side by side above the male die. The lower edges of these latter beams are oppositely cut away in a curve 35 to conform with the cut-away curve of the beams of the lower male die. This female die is adapted to be guided (not shown) in its vertical movement to receive and mate with the male die, a space (not shown) being left between the beams 34 and 34' to receive the knife plate.

The sheets 18 and 19, which are to form the sheathing of the boat, are each trimmed to shape, as indicated at 36 in Figure 9, and a hole 37 is provided at one end of each. This hole is also indicated in dotted outline in Figure 3. Each sheet is then placed separately between the dies, the portion forming the back part of the boat being received up the platform 31. The bow portion of the sheet is then positioned with the pin 29 of the male knife plate through the hole 37 thereof, to anchor this end, while the keel side of the sheet 38 contacts the guide stake 33. Suitable power means (not shown), such as a hydraulic ram, is then used to press the upper female die down onto the sheet and over the male die. As the sheet cannot move out of position, a groove, forming a tapered curved rib 39, is correctly formed across this portion, while at the same time the material moving into the female die pulls the sheet, or displaces the metal, into the correct bow-shape for one side of the boat. All this is done by the shape of the dies and no crinkling occurs along the edges of the sheets. Actually, a smooth ogee roll 40 emerges in the metal on each wall of the groove. The shape of this pressed rib 39 is clearly brought out in Figure 3, the dotted outline 41 showing the widest part. This wide part is cut away, as per the said dotted outline, to present a double thickness straight edge 42 in the direction of the end of the sheet, and a pair of short extending tongues 43. These tongues are then tapped back with a hammer to overlap, as shown at 44 in Figure 4. At the same time, the end of the sheet is turned inward in a flange 45, the width of the lap. The straight edges 42, for a portion there back, are then bent under in a fold and pressed tight, as indicated at 46 in dotted outline, and in full outline in Figure 7, to provide a water-tight joint. To further insure that the groove 39 will not open up, a hole is bored through the wall of this pressed rib, adjacent the straight edge fold, and a pair of blocks 47 are bolted thereto, one on the top and the other on the bottom.

All the sheets, for both sides of the boat, are cut to the same outer shape and provided with the hole 37 at one end, as shown in Figure 9. By observing Figure 8 it will be seen that the stake 33 is at the right end of the cross beam 30 so the dies are set for shaping a sheet for the right, or starboard, side of the boat. A left hand, or port, 'sheet is provided by simply turning a right hand sheet over onto its opposite side, changing the stake 33 to the opposite, or left hand end of the cross beam 30, and then passing the sheet through the dies, the keel side of the sheet always being held against the stake 33. After the ribs have been formed, their front ends are cut and shaped as shown in Figures 3 and 4. It will be particularly noticed that the holes 37 are in these cut-away portions. The sheets are then secured to the boat framework as shown in Figures 1, 2, 5 and 6 and previously explained. The blocks 47 are then attached, including the kcels, nosing strip, deck, seats, et cctera. As the grooved ribs 39 extend right up to the front part of the stem l1, or prow, they can also be used to support a shelf or shelving under the deck, if desired.

As the grooved ribs are formed directly from the sheets, without a break, and the cut-away straight edges bent over bow sides are water-tight, and '1 have manufactured and sold a considerable number of such boats without the use packing fabric or mastic at these from lapped parts, and

amazingly effective, a perfect dished shape being secured t without the sheet edges crinkling, and no other strengthening is required to maintain shape. The boat is not unbalanced and the downwardly observable groove line on the outside gives a rakish speedy appearance which enhances the bow design. The water 0-.' the bow wave, produced when the boat is moving, is inclined to enter the grooves and slide theredown, and so tend to cushion the shock, stop spray rising and entering the boat, and the passing water cleans the grooves to prevent dirt collection.

It will be appreciated however, that it would be a simple matter to insert packing fabric or the like in the grooves, or use mastic, if found desirable.

What 1 claim as my invention is:

l. The method of forming a bow side for a boat. from a sheathing blank, which consists in: die pressing a groove partially therealong to form an interior tapering rib from a rear flush position thereon to the prow-forming edge thereof, and in an outwardly bulging curve of varying depths to draw the correct amount of material therein and deform said blank into an outwardly projecting dished bow-shape; cutting off the prow corner of said rib, over lapping the cut walls thereof, and permanently clamping the remaining walls of said rib together thereat, to form a water-tight joint.

2. The method of forming a bow side for a boat from a sheathing blank, which consists in: placing the forward end of said blank between a pair of dies, and in anchored position on one; pressing an outwardly bulging, curved, tapered groove into said blank with said dies to form an interior rib which extends from a rear flush position thereon to the prowforming edge at the forward end thereof, and such that the increasing depths of the forming groove will draw the correct amount of material therein to deform said blank into an outwardly projecting dished bow-shape; removing an angular-shaped piece from the free side of said rib, adjacent said prow edge, and leaving a pair of short extending tongues at said edge; forming said latter edge into a side flange, including said tongues, which overlap; and subsequently overlapping the cut walls of said rib and permanently clamping the re maining walls thereof together thereat, to form a watertight joint.

References Cited in the file of this patent UNITED STATES PATENTS 1,790,624 Shoup I an. 27, 1931 2,166,226 Vehko Jan. 18, 1939 2,326,283 Bonsali Aug. 10, 1943 2,339,355 Rutten Jan. 18, 1944 portions 41 have their in laps and firmly pressed, the 

